Detection of intentional sub-optimal performance on a computerized finger-tapping task

Psychomotor function in children with epilepsy seen at a tertiary hospital in southern Nigeria: does treatment with anti-epileptic drugs have any effect?

Background

Psychomotor slowing is more commonly reported in children with epilepsy (CWE) compared to healthy controls. The effect of anti-epileptic drug (AED) treatment on psychomotor abilities of CWE remains controversial. In Nigeria, psychomotor abilities of CWE are scarcely investigated and the impact of AEDs is not known. The present study sought to assess psychomotor performance of CWE compared to healthy controls and to determine any association with seizure characteristics and treatment.

Method

A comparative cross-sectional study involving 160 children with idiopathic epilepsy and 80 controls aged 6–16 years. Psychomotor function was assessed using reaction times and tapping task of the Iron psychology computerised test battery. The criterion for impairment was fixed at two standard deviations (SD) worse than the mean of age-matched controls. The relationship between seizure variables and psychomotor function was assess with the one-way analysis of variance (ANOVA).

Result

Fifty-nine (36.9%) CWE had impaired auditory reaction, 50 (31.3%) with impaired visual reaction and 11 (6.9%) had fine motor control impairment. There was no significant difference in psychomotor performance between CWE on AED and the newly diagnosed counterparts yet to start AED treatment (auditory reaction time—p = 0.226; visual reaction time—p = 0.349; tapping task—p = 0.818). AED treatment duration over 5 years was associated with better auditory reaction time (F = 4.631, p = 0.034) in CWE. Also, seizure onset before 5 years of age was associated with slower auditory reaction (F = 4.912, p = 0.028) and verbal reaction (F = 14.560, p < 0.001).

Conclusion

Nigerian CWE perform less favourably on tests of psychomotor function than healthy controls. The performance of children on AED is not significantly different from those not on AED. Longer duration of AED treatment may result in psychomotor improvement in CWE. CWE should be closely monitored for psychomotor slowness so that deficits can be identified and appropriate interventions instituted.

Computerized measures of finger tapping: reliability, malingering and traumatic brain injury

We analyzed computerized finger tapping metrics in four experiments. Experiment 1 showed tapping-rate differences associated with hand dominance, digits, sex, and fatigue that replicated those seen in a previous, large-scale community sample. Experiment 2 revealed test-retest correlations (r = .91) that exceeded those reported in previous tapping studies. Experiment 3 investigated subjects simulating symptoms of traumatic brain injury (TBI); 62% of malingering subjects produced abnormally slow tapping rates. A tapping-rate malingering index, based on rate-independent tapping patterns, provided confirmatory evidence of malingering in 48% of the subjects with abnormal tapping rates. Experiment 4 compared tapping in 24 patients with mild TBI (mTBI) and a matched control group; mTBI patients showed slowed tapping without evidence of malingering. Computerized finger tapping measures are reliable measures of motor speed, useful in detecting subjects performing with suboptimal effort, and are sensitive to motor abnormalities following mTBI.